The present disclosure relates generally to phase shifters. More particularly, the present application relates to a phase shifter that may be used in an electronically scanned array and in other devices that require ultra-high precision phase control.
Phase shifters are used in a variety of applications. In one example, a phase shifter may be used in a wired network to match signal phases across coaxial cables. In another example, phase shifters may be used in a speaker system to account for different distances between a human user and the various speakers (e.g., so that the sounds heard by the user are phase matched). In a further example, a phase shifter may be used in a motor controller to control the phases of the motor's input voltages.
Phase shifters generally fall into two categories: analog phase shifters and digital phase shifters. Analog phase shifters allow for a continuously variable phase, but are typically susceptible to noise. Digital phase shifters are typically less susceptible to noise than their analog counterparts, but only allow for discrete phase shifts. For example, a digital phase shifter may only allow for phase shifts in forty five degree increments. Applicants have discovered that there may be a need for an ultra-precise phase shifter that approaches the controllability of an analog phase shifter, while maintaining the immunity to noise of a digital phase shifter.